time/debug: Fix memory leak with using debugfs_lookup()

[ Upstream commit 5b268d8aba ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic at
once.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230202151214.2306822-1-gregkh@linuxfoundation.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

kernel/time/test_udelay.c

@@ -149,7 +149,7 @@ module_init(udelay_test_init);
 static void __exit udelay_test_exit(void)
 {
 	mutex_lock(&udelay_test_lock);
-	debugfs_remove(debugfs_lookup(DEBUGFS_FILENAME, NULL));
+	debugfs_lookup_and_remove(DEBUGFS_FILENAME, NULL);
 	mutex_unlock(&udelay_test_lock);
 }